Canon sx40 accessories

Please can I have some advice on the merits of buying a .45x wide angle macro lens, a 2x tele adaptor and a speedlite flash (advice on best option?) as accompaniments to the sx40 I am bout to buy. It is a very versatile camera so are these accessories going to make a meaningful difference? My interests are wildlife small and large, birds and general scenery as well as usual family shots. I am going for additional batteries (not canon), 2x 8g cards (i am looking at transcend brand is that best i can get) a linear density polarizing lens, tripod plus case as mandatories. Am I missing anything?
Many thanks for your help
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Cheers Ian